WO2007029135A2 - Controlling an optical disc drive - Google Patents
Controlling an optical disc drive Download PDFInfo
- Publication number
- WO2007029135A2 WO2007029135A2 PCT/IB2006/052975 IB2006052975W WO2007029135A2 WO 2007029135 A2 WO2007029135 A2 WO 2007029135A2 IB 2006052975 W IB2006052975 W IB 2006052975W WO 2007029135 A2 WO2007029135 A2 WO 2007029135A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- moving part
- data relating
- reliable
- disc drive
- optical disc
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/02—Control of operating function, e.g. switching from recording to reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B21/00—Head arrangements not specific to the method of recording or reproducing
- G11B21/02—Driving or moving of heads
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
Definitions
- the invention relates to the field of controlling optical disc drives. More specifically, the invention describes a method for controlling homing actions related to moving parts of an optical disc drive, and an optical disc drive with improved homing performance.
- An optical drive may comprise several stepping motor controlled moving parts, such as an optical pick-up unit (OPU), a collimator in the optical path of the OPU, radial and/or tangential tilt mechanisms, as well as disc tray, etc.
- OPU optical pick-up unit
- a collimator in the optical path of the OPU radial and/or tangential tilt mechanisms, as well as disc tray, etc.
- radial and/or tangential tilt mechanisms as well as disc tray, etc.
- This homing sensor can be a mechanical switch or an electrical measurement (e.g. back-EMF or current measurement). It is difficult to manufacture and/or tune such a sensor for a number of reasons.
- a mechanical switch has a considerable position tolerance, an electrical measurement can be (too) late to detect a mechanical stopper.
- To control a stepping motor a sine and cosine signal must be provided to the coils of the stepping motor. This sine and cosine signal must be in phase with the magnetic angle of the stepping motor. However, after power up this angle is not known. As a consequence of the above difficulties the homing can have large tolerances so that extra calibrations are needed after start-up.
- a "blind homing" without any control of the actual position of the moving part may include the moving part hitting a mechanical stopper which may limit the working life of the optical disc drive.
- US 4,706,008 discloses an optical disc drive with a memory for storing a phase state of the motor driving the moving part of the optical disc drive, and a flip-flop is used to detect if a start-up is a "cold start". Only after a "cold start” a blind homing will be performed, and thus the number of blind homing actions may be reduced. However, e.g. if the moving part is moved by an external force (e.g.
- US 2004/0013053 discloses an optical disc drive with a moving part where a position memory is updated for each movement of the moving part performed by the driving motor. Still, the same problem exists as described for the optical disc drive of US 4,706,008, namely that the optical disc drive will loose control of the actual position of the moving part, if the moving part is moved by an external force (e.g. in case of a shock).
- This invention describes a method of storing the position of a moving part so that the position is still known after power down.
- a first aspect of the invention provides a method for controlling a moving part of an optical disc drive, the method comprising the steps of
- a reliability register e.g. a one bit register or memory, which is used to indicate whether stored data relating to the position of the moving part are reliable or un-reliable
- Performing a blind homing is only necessary in case this reliability register indicates that stored position data are un-reliable and therefore invalid to use.
- a blind homing is not necessary; controlled homing actions can be used instead of blind homing actions. This saves time, and it can be ensured that the moving part avoids hitting a mechanical stop.
- the reliability register After having performed the blind homing in step 2) and subsequent updating the position data, the reliability register is set to "un-reliable". This is advantageous since in case of any failure, meaning a failure which can result in unreliable sledge position, e.g. a shock causing an unintended movement of the moving part, the reliability register will indicate in such situation that the stored position data are un-reliable and therefore a blind homing is required.
- blind homing will only be performed in special situations. For example a blind homing is necessary in case of power failure during normal operation. In such a situation the next start-up will be followed by a blind homing action. Another example is when a disc is found to be present but the disc can not for some reason be recognized, i.e. start-up failed. In such situation it is not 100% sure that the position of the moving part is still reliable, and therefore it is preferred that the subsequent start-up is followed by a blind homing.
- the method further comprises the steps of
- the reliability register indicates that the stored position data are valid, and therefore these position data can be read and used to adjust setting of the motor driving the moving part in accordance therewith.
- the method further comprises the step of
- a controlled homing i.e. performing a controlled movement of the moving part to a predefined position using knowledge of its actual position, is advantageous to perform after a stop command has been received.
- time for a homing action is saved upon receipt of the next start command, and thus the optical disc drive is capable of responding faster to a start command in normal operation.
- non- volatile memory (which is needed because a uncontrolled power off should also handled correctly) may be limited to a minimum: only during start-up (reliability register) and stop (position and reliability register).
- start-up reliability register
- stop position and reliability register
- EEPROM electrically erasable programmable read-only memory
- an EEPROM may have a specified upper limit of 5000 times of writing actions.
- the mentioned controlled homing action further comprises the steps of
- the controlled homing is verified and in case no errors occurred during movement of the moving part to the predefined homing position, data relating to the position of the moving part is updated and the reliability register is set to "reliable" thus indicating that at a subsequent start-up it is possible to utilize the stored position data instead of performing a blind homing.
- the information angle, reliability
- the data relating to the position of the moving part comprise data relevant to adjusting the settings of a motor driving the moving part.
- the relevant data may comprise a value indicating a magnetic angle of the stepping motor.
- the invention provides an optical disc drive comprising a moving part, a motor for driving the moving part, non- volatile memory for storing data relating to the position of the moving part, a reliability register for storing whether the data relating to the position of the moving part are reliable, adjusting means for reading the memory and adjusting settings of the motor according to the data read from the memory in case the reliability register indicates that data are reliable.
- An optical disc drive is capable of utilizing the advantages described above in connection with the first aspect.
- the reliability register and the memory may be implemented using a non- volatile type of memory such as a flash memory and/or an Electrically Erasable Programmable Read Only Memory (EEPROM) which will always be present in connection with an optical disc drive.
- the reliability register only needs to be one bit (e.g. 0 indicating "un-reliable” and 1 indicating "reliable"), and appropriate data relating to a position of the moving part may be stored using such as only 8 bit or another relevant number of bits to represent e.g. a magnetic angle of the motor.
- the memory uses 1 bit for the reliability bit and 7 bits to represent the magnetic angle of the motor.
- the adjusting means may be implemented as a part of an existing routine, i.e. software, for controlling an optical disc drive.
- the moving part can be one or more of: an optical pick-up unit, a collimator in an optical path of an optical pick-up unit, a radial tilt mechanism, a tangential tile mechanism, a disc tray.
- the motor driving the moving part comprises a stepping motor
- the memory is capable of storing a value representing a magnetic angle of the stepping motor.
- the motor may comprise a e.g. a tacho controlled brush(less) DC motor and store the position of the moving part of the DC/AC motor and just store the reliability of the position when stopped.
- the invention provides an electronic chip for an optical disc drive, the electronic chip comprising a non- volatile memory for storing data relating to the position of a moving part of the optical disc drive, - a reliability register comprising at least one bit for storing whether data relating to the position of the moving part are reliable, a controller adapted to read the reliability register whether data stored in the memory are reliable, upon a start-up command being received, and in case the reliability register indicates that the stored data are un-reliable, the controller is adapted to: - initiate a blind homing of the moving part of the optical disc drive, store in the memory data relating to the position of the moving part, and in case the reliability register indicates that the stored data are reliable, the controller is adapted to: - store in the reliability register that the stored data relating to the position of the moving part are un-reliable.
- the electronic chip may be implemented as one single chip or alternatively, the features may be spread to two or more chips, i.e. a chip set for an optical disc drive.
- the one or more chips with the features according to the third aspect may be integrated into chips that provide other functionalities related to the optical disc drive and optionally other devices.
- the invention provides a device comprising an optical disc drive, the optical disc drive comprising a moving part, a motor for driving the moving part, a non- volatile memory for storing data relating to the position of the moving part, a register for storing whether the data relating to the position of the moving part are reliable, - adjusting means for reading data relating to the position of the moving part from the memory and adjusting settings of the motor in accordance herewith.
- the device may be such as player and/or recorders for CDs, DVDs, BD, HD- DVD and equivalents and variant thereof together with magnetic storage devices.
- the device may be an audio device, a video device, combined audio/video devices or data storage devices.
- a non-exhaustive list of device examples are: CD players, SACD players, DVD players/recorders, BD players/recorders, HD-DVD players/recorders, hard disc recorders, TV sets with built in optical storage means, CD ROM or DVD recorders for computers.
- the invention provides a computer readable program code for use in combination with an optical disc drive having a moving part, the computer readable program code being adapted to
- the computer readable program code may be implemented together with existing code adapted to control the function of an optical disc drive.
- the program code may be present on a storage medium or stored in a RAM or ROM memory.
- Fig. 1 illustrates a block diagram of an optical disc drive embodiment according to the invention
- Fig. 2 illustrates a flow chart showing a preferred algorithm for control of homing in an optical disc drive.
- Figure 1 shows vital part of a preferred embodiment of an optical disc drive according to the invention.
- a motor MTR is connected to drive a moving part MP of the optical disc drive.
- the motor MTR may be a stepping motor and the moving part MP may be a disc tray that is mounted to perform a linear motion.
- An actual position of the moving part MP is crucial with respect to adjust electrical signals to the motor MTR.
- a memory MEM preferably a non- volatile type memory, is used to store data relating to the position of the moving part MP once a reliable position of the moving art MP has been obtained. It should be mentioned that the writing actions to a non-volatile memory must be limited.
- the data relating to the position of the moving part MP may comprise such as a displacement in mm from a fixed homing position or more advantageously, the data may comprise data that are directly relevant with respect to control of the motor MTR, e.g. a magnetic angle in case of a stepping motor.
- adjusting means ADJ e.g. a microprocessor circuit, to read the memory MEM and adjust settings of the motor MTR according to the data read from the memory MEM. If e.g. a displacement from a fixed homing position of the moving part MP is stored, then the adjusting means ADJ will need to calculate or translate this displacement into a value relevant with respect to adjusting settings for controlling the motor MTR in accordance thereto.
- the motor MTR Since normally the motor MTR is directly mechanically connected with the moving part MP, there will be a direct connection between a position of the moving part MP and e.g. a magnetic angle of the motor MTR in case it is a stepping motor. However, knowing only for instance a magnetic angle of a stepping motor, additional data relating to the position of the moving part MP is required in order to be able to bring the moving part MP to a desired position, since the same magnetic angle of the motor MTR may correspond to several positions of the moving part MP. Thus, e.g. moving the sledge to a 26 mm radius during the controlled homing C hom it is only needed to have this information hard coded available in the firmware of the drive. Only the angle information is needed in the nonvolatile memory.
- a reliability register REL reg is associated with the memory MEM. This register REL reg is preferably one bit indicating if the data in memory MEM are reliable or un-reliable.
- the adjusting means ADJ Prior to reading data from the memory MEM for updating motor settings, the adjusting means ADJ checks the reliability register REL reg. If the register REL reg indicates that data are reliable, then the adjusting means ADJ can read data from the memory MEM and motor settings can be updated in accordance therewith.
- the adjusting means ADJ may initiate a blind homing action so as to regain track of position of the moving part MP and subsequently store position data in memory MEM once a successful blind homing actions has been performed.
- the adjusting means ADJ, the memory MEM and the reliability register REL reg may be an integral part of the optical disc drive or implemented entirely or partially using a separate chip set comprising one or more separate electronic chips.
- Figure 2 shows a flow chart of a preferred algorithm for control of an optical disc drive according to the invention.
- the algorithm will be explained in the following assuming an optical disc drive with the elements as described in connection with Figure 1.
- the algorithm is an example where a moving part of the optical disc drive is driven by a stepping motor.
- the first step R rb Upon receipt of a start-up command St com, the first step R rb is to read a reliability bit. This answers the questions P r? if position of the moving part is reliable or not. In case of yes Y, the next step Rp ma of reading the motor angle from memory. This information will be used to preset the phase of the sine and cosine signal needed to control the stepping motor. In case the answer to question P r? is no N, then a blind homing B hom is performed instead. This will be the case e.g. with a fatal error caused by a large external shock or caused by an unwanted power shut down.
- next step Rb nr is to set the reliability bit to "un-reliable", i.e. not reliable.
- the reliability bit is set to "unreliable” after a blind homing B hom or alternatively an Rp ma step is performed. This will allow position changes of the moving part when needed.
- the next step D ree is a disc recognizing procedure, which will not be described in further detail since it is not important with respect to the invention.
- Next step D_p? is to check whether a disc is present. If yes Y, then it is checked St f? whether start-up has failed. If start-up St f?
- the wanted reaction of the drive is then as follows: When the reliability bit indicates that the position is not reliable a blind homing is performed and the drive detects that there is no disc available. Normally, the position is not changed and the reliability bit will be written to 1 (reliable). A second start-up (reliability bit indicates that the position is reliable) will be done without a homing. In conclusion, even if the start-up will fail because there is no disc (this occur very frequently) no extra blind homing is needed.
- the step P c? is omitted because when there is no disc available the sledge position should always be in control. This is because the action Rp ma or B hom will lead to that C Hom can be done (often 0 displacement of course) and H r? is therefore always yes Y.
- a controlled homing C hom i.e. a controlled movement of the moving part to its homing position.
- H r a controlled movement of the moving part to its homing position.
- the algorithm ends E. If the home position is considered reliable Y, then next step S ma is to store the current motor angle in memory and the reliability bit is set to "reliable" Rb r.
- a subsequent start-up command St com will at first instance utilize the stored data Rp ma, since the reliability bit will indicate that data are "reliable", and the question P r? will be answered by yes Y. The reliability bit will then be set to "unreliable" Rb nr. However, due to the changed position, the start-up will fail, the answer to the question St f? will therefore be yes Y, and the algorithm will end. A subsequent start-up command St com will result in a blind homing B hom, since now the reliability bit will indicate "un-reliable", and the answer to question P r? will be no N.
- the described algorithm will be easily implemented in software code such as a part of existing code for controlling an optical disc drive.
- the algorithm has been described in details in connection with an application using a stepping motor.
- the algorithm or part of the algorithm can also be used for other kind of motors used in a closed or open loop type of control loop.
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- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/065,763 US20080253243A1 (en) | 2005-09-06 | 2006-08-28 | Controlling an Optical Disc Drive |
EP06795794A EP1927104A2 (en) | 2005-09-06 | 2006-08-28 | Controlling an optical disc drive |
JP2008529723A JP2009507325A (en) | 2005-09-06 | 2006-08-28 | Optical disk drive control |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP05108132 | 2005-09-06 | ||
EP05108132.1 | 2005-09-06 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2007029135A2 true WO2007029135A2 (en) | 2007-03-15 |
WO2007029135A3 WO2007029135A3 (en) | 2007-06-07 |
Family
ID=35285351
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2006/052975 WO2007029135A2 (en) | 2005-09-06 | 2006-08-28 | Controlling an optical disc drive |
Country Status (7)
Country | Link |
---|---|
US (1) | US20080253243A1 (en) |
EP (1) | EP1927104A2 (en) |
JP (1) | JP2009507325A (en) |
KR (1) | KR20080043399A (en) |
CN (1) | CN101258543A (en) |
TW (1) | TW200717455A (en) |
WO (1) | WO2007029135A2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008130202A (en) * | 2006-11-24 | 2008-06-05 | Toshiba Corp | Reproducing position control circuit and reproducing system |
CN115061415B (en) * | 2022-08-18 | 2023-01-24 | 赫比(成都)精密塑胶制品有限公司 | Automatic process monitoring method and device and computer readable storage medium |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4706008A (en) * | 1986-12-11 | 1987-11-10 | Ibm Corporation | Self-adjusting homing for a stepping motor |
US20040013053A1 (en) * | 2002-07-19 | 2004-01-22 | Samsung Electronics Co., Ltd. | Method and apparatus for controlling home-in mode in disc drive |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000230821A (en) * | 1999-02-08 | 2000-08-22 | Sony Corp | Method for detecting location of moving body and disk drive device |
-
2006
- 2006-08-28 CN CNA200680032583XA patent/CN101258543A/en active Pending
- 2006-08-28 WO PCT/IB2006/052975 patent/WO2007029135A2/en active Application Filing
- 2006-08-28 US US12/065,763 patent/US20080253243A1/en not_active Abandoned
- 2006-08-28 EP EP06795794A patent/EP1927104A2/en not_active Withdrawn
- 2006-08-28 KR KR1020087008323A patent/KR20080043399A/en not_active Application Discontinuation
- 2006-08-28 JP JP2008529723A patent/JP2009507325A/en active Pending
- 2006-09-01 TW TW095132419A patent/TW200717455A/en unknown
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4706008A (en) * | 1986-12-11 | 1987-11-10 | Ibm Corporation | Self-adjusting homing for a stepping motor |
US20040013053A1 (en) * | 2002-07-19 | 2004-01-22 | Samsung Electronics Co., Ltd. | Method and apparatus for controlling home-in mode in disc drive |
Also Published As
Publication number | Publication date |
---|---|
EP1927104A2 (en) | 2008-06-04 |
JP2009507325A (en) | 2009-02-19 |
TW200717455A (en) | 2007-05-01 |
CN101258543A (en) | 2008-09-03 |
US20080253243A1 (en) | 2008-10-16 |
KR20080043399A (en) | 2008-05-16 |
WO2007029135A3 (en) | 2007-06-07 |
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